+ (and binding (format nil "~a" (cdr binding)))))
+
+(defun lookup-variable (symbol env)
+ (or (ls-lookup symbol env)
+ (ls-lookup symbol *env*)
+ (error "Undefined variable `~a'" symbol)))
+
+(defun lookup-function (symbol env)
+ (or (ls-lookup symbol env)
+ (ls-lookup symbol *fenv*)
+ (error "Undefined function `~a'" symbol)))